Simulation Experiments on the Reaction of CH_4-CaSO_4 and Its Carbon Kinetic Isotope Fractionation

Thermochemical sulfate reduction (TSR) in geological deposits can account for the accumulation of H2S in deep sour gas reservoirs. In this paper, thermal simulation experiments on the reaction of CH4-CaSO4 were carried out using an autoclave at high temperatures and high pressures. The products were characterized with analytical methods including carbon isotope analysis. It is found that the reaction can proceed to produce H2S, H2O and CaCO3 as the main products. Based on the experimental results, the carbon kinetic isotope fractionation was investigated, and the value of Ki (kinetic isotope effect) was calculated. The results obtained in this paper can provide useful information to explain the occurrence of H2S in deep carbonate gas reservoirs.

Characterization of [bmim]Cl/FeCl_3 Ionic Liquid with Spectra

bmim]Cl/FeCl3 ionic liquids (where bmim = 1-butyl-3-methylimidazolium) were characterized by XPS (X-ray photoelectron spectroscopy), FT-IR (Fourier transform infrared spectroscopy), Raman and NMR (nuclear magnetic resonance) spectra. The results show that Fe2Cl7 and FeCl4 ions are the principal anions in acidic ionic liquids, - - whose concentrations change with the content of FeCl3 and an equilibrium exists between them. An isosbestic point existing in FT-IR spectra indicates that an interaction involving at least two species occurs and their concentrations vary with acidity. Chemical shifts of the hydrogen located in the cations of ionic liquids are sensitive to the composition of ionic liquids. The change in chemical shifts may be explained in terms of anion-cation interactions. The chemical shifts of 2-H are affected by metal halides, which shift downfield and the 2-H is more deshielded with the increase in metal halides.

Isomerization of n-octane on NiW/HSAPO-11 Catalyst

The catalyst NiW/HSAPO-11 was prepared by impregnating Ni and W onto HSAPO-11 zeolite with two different methods. The isomerization and aromatization properties were investigated with an microreactor using n-octane as a feedstock. NiW/HSAPO-11 shows a high hydroconversion activity of n-octane, and the optimum operating parameters for the catalyst to produce high octane number products were: 400℃, 2.0MPa, VH2:Vn-octane= 400:1, liquid hourly space velocity LHSV=1.0h-1. Under the optimum reaction condition, the conversion efficiency, C5 liquid + product selectivity, isomerization and aromatization product selectivity were 69.80%, 56.95%, 79.73% and 1.29% respectively. The catalyst (S1) impregnated with Ni and W after the HSAPO-11 zeolite was combined with Al2O3 matrix, performed better than the catalyst (S2) impregnated with Ni and W before combining with the Al2O3 matrix.

A Study of the Adsorption of Molecular Deposition Filming Flooding Agent MD-1 on Quartz Sand

Molecular deposition filming flooding (MDFF) is a novel oil recovery technique based on the thermopositive monolayer electrostatic adsorption of the MDFF agent on different interfaces within reservoir systems. In this paper, the adsorption property of the MDFF agent, MD-1, on quartz sand has been studied through adsorption experiments at different pH and temperatures. Experimental data are also analyzed kinetically and thermodynamically. The results show that the adsorption of MD-1 on quartz sand takes place mainly because of electrostatic interactions, which corresponds to adsorption that increases with pH. Kinetic analyses show that at a higher pH the activation energy for adsorption gets lower and, therefore, the adsorption becomes quicker for MD-1 on quartz sand. Thermodynamic analyses show that pH plays an important role in the adsorption of MD-1 on quartz sand. At a higher pH, more negative surface charges result in the increase of electrostatic interactions between MD-1 and quartz sand. Therefore, the saturated adsorption amount increases and more adsorption heat will be released.

A Study of Gas Diffusion Electrodes for the Coupled Reaction of Water Electrolysis and Electrocatalytic Benzene Hydrogenation

Gas diffusion electrodes are applied to the coupled reaction of water electrolysis and electrocatalytic benzene hydrogenation. The effects of the preparation conditions of electrodes, electrolyte acidity, the concentration of benzene and water vapor, and the flow rate of N2 are investigated by evaluating the efficiency of the current. Furthermore, the optimal operational conditions have been ascertained. The results of our experiment show that gas diffusion electrodes have good performance when the content of PTFE is 10% (wt) and that of Nafion is 0.75mg/cm2. The optimal operational conditions are as follows: The temperature of electrolysis is 70℃, acidity 0.5mol/L, the concentration of benzene 26%, the concentration of vapor 10%, the flow rate of N2 80mL/min-240mL/min. The efficiency of the current can reach 35% under optimal operational conditions. Then, a conclusion can be drawn that gas diffusion electrodes can improve the rate of the coupled reaction effectively.

A CFD Model for Fluid Dynamics in a Gas-fluidised Bed

A modified particle bed model derived from the two-fluid momentum balance equations was employed to predict the gas-fluidised bed behaviour. Additional terms are included in both the fluid and the particle momentum balance equations to take into account the effect of the dispersed solid phase. This model has been extended to two-dimensional formulations and has been implemented in the commercial code CFX 4.3. The model correctly simulates the homogeneous fluidisation of Geldart Group A and the bubbling fluidisation of Geldart Group B in gas-solid fluidised beds.

FT-IR Study of Carbon Nanotube Supported Co-Mo Catalysts

In this paper, adsorption properties of dibenzothiophene (DBT) on carbon nanotube, carbon nanotube supported oxide state and sulfide state CoMo catalysts are studied by using thermal gravimetric analysis (TGA) technique and FT-IR spectroscopy. Activated carbon support, γ-AlgO3 support and supported CoMo catalysts are also subjected to studies for comparison. It was found that sulfide state CoMoS/MWCNT, CoMoS/AC and CoMoS/γ-Al2O3 catalysts adsorbed much more DBT molecules than their corresponding oxide state catalysts, as well as their corresponding supports. The chemically adsorbed DBT aromatic molecules did not undergo decomposition on the surface of supports, supported oxide state CoMo catalysts and sulfide state CoMo catalysts when out-gassing at 373 K. FT-IR results indicated that DBT molecules mainly stand upright on the active sites (acid sites and/or transition active phases) of CoMoS/MWCNT catalyst. However, DBT aromatic molecules mainly lie flat on MWCNT and CoMoO/MWCNT.

A New Mathematical Simulation Approach for Thermal Cracking Furnace Studies

Thermal cracking of hydrocarbons for olefin production is normally carried out in long reactor tubes suspended in a large gas fired furnace. In this paper, a coupled furnace-reactor mathematical model based on a computational fluid dynamics (CFD) technique is developed to simulate the complex fluid dynamics phenomena in the thermal cracking furnace. The model includes mass transfer, momentum transfer, and heat transfer, as well as thermal cracking reactions, fuel combustion and radiative heat transfer. The rationality and reliability of the mathematical model is confirmed by the approximate agreement of predicted data and industrial data. The coupled furnace-reactor simulation revealed the details of both the transfer and reaction processes taking place in the thermal cracking furnace. The results indicate highly nonuniform distribution of the flue-gas velocity, concentration and temperature in the furnace, which cause nonuniform distribution of tube skin temperature and heat flux of the reactor tubes. Profiles of oil-gas velocity, pressure, temperature and product yields in the lengthwise direction of the reactor tube are obtained. Furthermore, in the radial direction steep velocity and temperature gradients and relatively slight gradients of species concentration are found. In conclusion, the model can provide more information on the fluid dynamics and reaction behavior in the thermal cracking furnace, and guidance for the design and improvement of thermal cracking furnaces.

Catalytic Performance of Bare Supporters and Supported KVO_3 Catalysts for Cracking n-Butane to Produce Light Olefins

Supported KVO3 catalysts were prepared by impregnating different kinds of supporters (α-Al2O3, γ-Al2O3 and SiO2 powders) with a KVO3 solution. The activity of the bare supporters and supported catalysts were evaluated in a continuous micro-reactivity test unit, with n-butane as a raw material. The results show that KVO3 has no catalytic activity, but it can increase the selectivity to light olefins. The supporter of α-Al2O3 has good catalytic performance for n-butane cracking when the reaction temperature is below 700℃.

Study of Modification and Performance of HZSM-5 Catalyst for Isomerization of Light Paraffin

The isomerization of light paraffin over HZSM-5-Ni-Mo-F synthetic zeolite catalysts was studied, and the effects of reaction conditions on the isomerization were investigated. The results show that the optimum reaction condition can be obtained to enhance the research octane number (RON) of product and the liquid yield. The optimum experimental condition is: HZSM-5 catalyst with 1.5wt% of Ni, 2wt% of Mo and 0.4wt% of F, at a temperature of 345℃ and a reaction mass hourly space velocity (MHSV) of 0.2 h-1. The isomerization reaction of light paraffin from Tarim refinery was studied and the research octane number (RON) of gasoline product could be enhanced by 20 units under the condition of nonhydrogenization and optimum experimental status.

X-Ray Absorption Spectroscopy of Mo and Ni K-edge of Supported Hydrotreating Catalysts

X-ray absorption fine structure (XAFS) and other techniques have been used to characterize Ni-Mo/Al2O3 supported catalysts. The analysis of Mo K-edge spetrum shows that the active species over sulfide catalysts are MoS2-alike and the dispersion of Mo is high at the level of nanometer particles. There may exist some distortion of the local environment of MoS2, which has an influence on the hydrotreating activities of catalysts. Ni K-edge analysis shows that the coordination effects of Ni-Mo favor the dispersion state of active phase and imply a close relationship with catalyst activities.

Synthesis and Characterization of Self-Assembled V_2O_5 Mesostructures Intercalated by Polyaniline

A new nanocomposite of vanadium pentoxide (V_2O_5) and polyaniline (PANI)were synthesized by in situ oxidative polymerization/intercalation on V_2O_5 powder at roomtemperature. The reaction was facile and topotactic, forming polyaniline as the emeraldine salt. Itwas indicated that V_2O_5 itself can catalyze the oxidative polymerization of aniline and thatlayered structure could make aniline intercalate into the V_2O_5 framework. It makes the in situpolymerization feasible to occur in the layer of V_2O_5 structure. XRD results showed PANI/V_2O_5nanocomposite possessed lamellar mesostructure, which was determined by an X-ray diffraction peak at6.5° and SEM photograph. And FT-IR spectrum suggested that there was interaction between PANI andV_2O_5. The hybrid had better thermal stability in N_2 and air ambience.

Advances in Synthesis of Mesostructured Aluminophosphates

More and more attention has been paid to the synthesis of mesostructuredaluminophosphates for many years. A lot of valuable research results, including various syntheticapproaches and structural materials, have been obtained. This paper reviews the progress in thesynthesis of mesostructured aluminophosphates over the past few years, with the hope of revealingopportunities for future work.

Preparation of Core-shell Structured Particles and Their Nucleation in Polyester:I. Preparation of Monodisperse SiO_2/PS Core-shell Composite Particles

To enhance the nucleation and crystallization properties of polyester (e.g., polyethylene terephthalate, PET), core-shell structured particles are used to improve these properties by controlling the inorganic dispersion properties in the polymers. In the paper, monodisperse particles of silica/polystyrene (PS) are prepared with both dispersion and emulsion polymerization techniques. The monodisperse silicon dioxide particles are first prepared with the seed growth method and modified by the coupling agents. Silica is properly modified with KH-570, and its size deviation is 3.0% or so. The modified silica then reacts with the mixture of ethanol, water medium, and monomer of styrene under dispersion polymerization. Results show that the dispersion polymerization technique is more suitable for monodisperse core-shell SiO2/PS particles than that of the emulsion. The morphology and molecular structure of the core-shell particles are investigated with the transmission electron microscope (TEM), and fourier transform infra-red spectroscopy (FTIR). The results show that the modified silica particles are successfully encapsulated with polystyrene. The average number of silica particles encapsulated into each polystyrene sphere decreases when the size of silica particles increases from 50 nm to 600 nm, and will approach one when the silica is greater than 380nm in size. The mass ratio for silica/PS particles in emulsion polymerization is 4.7/1, lower than that of 6.8/1 for dispersion polymerization, which is the first reported optimized data for preparing the similar monodisperse composite particles. Thus, the PS shell in the former is thinner than that in the latter.

Influence of Solvent Conditons on Average Relative Molecular Weight of Polyoctadecyl Acrylate

Polymerization of octodecyl acrylate is studied in four solvents — carbon tetrachloride, chloroform, methylbenzene and tetrachloroethane. Experimental results indicate that the sequence of chain transfer constants in solvents is: carbon tetrachloride>chloroform>methylbenzene>tetrachloroethane in the polymerization of octadecyl acrylate. Influences of four solvents on solubility of polyoctadecyl acrylate prove not the same. In chloroform, polyoctadecyl acrylate shows the highest relative viscosity and the lowest chain termination rate constant. In higher conversion, the average relative molecular weight of polyoctadecyl acrylate depends mainly on the chain transfer constant of the solvent. Under the circumstance of monomer conversion higher than 30%, the viscosity effect induced by polymeric molecular shape in the solvents have a strong influence on the relative molecular weight of the polymer obtained.

Origin of Unliberated Bitumen in Athabasca Oil Sands

Oil sands contain a so-called organic rich solids component (ORS), i.e., solids whose surfaces are strongly associated with toluene insoluble organic matter (TIOM). Typically, humic material is the major component of TIOM. It provides sites for adsorption and chemical fixation of bitumen. This bound bitumen is “unliberated”, and considerable mechanical or chemical energy may be required to release it. In order to establish a correlation between bitumen recovery and ORS content, a few selected oil sands were processed in a Batch Extraction Unit (BEU). Analysis of the middlings and coarse tailings streams from these tests indicated a relatively constant bitumen to ORS ratio of 2.8±0.7. This value allows the liberated-unliberated bitumen balance (LUBB) to be calculated for any given oil sands. The amounts of bitumen recovered as primary froth during the BEU experiments are close to the estimated liberated bitumen contents in each case tested. This observation indicates that the liberated-unliberated bitumen calculation is an important quantitative parameter for prediction of bitumen recovery under specific recovery conditions. Preliminary results indicate that the ORS content of an oil sands may be estimated from the carbon content of bitumen free oil sands solids.